US blockade of Iran will be major military endeavor, experts say

WASHINGTON – A U.S. naval blockade of Iran would be a major, open-ended military operation that could trigger retaliation from Tehran and further strain an already fragile ceasefire, experts said.

President Donald Trump, in a social media post following unsuccessful peace talks in Islamabad over the weekend, said the U.S. Navy “will begin the process of BLOCKADING any and all ships trying to enter or leave the Strait of Hormuz.”

The U.S. military’s Central Command later clarified that the blockade would apply only to vessels traveling to or from Iran, including Iranian ports in the Arabian Gulf and Gulf of Oman. It said the measure would take effect on Monday at 10 a.m. in Washington (1400 GMT).

Trump also said U.S. forces would intercept vessels that had paid fees to Iran, even if they were already in international waters. “No one who pays an illegal toll will have safe passage on the high seas,” he wrote on Truth Social.

The stated objective, according to Trump, is to pressure Iran to reopen the Strait of Hormuz, a critical oil shipping route that handles roughly 20% of global crude flows and has been effectively restricted to vessels cleared by Tehran.

If successful, the strategy could weaken Iran’s leverage in negotiations and restore normal shipping through the strait, potentially easing global oil prices. However, analysts warned that enforcing a blockade would amount to an act of war and require a sustained deployment of significant naval forces.

“Trump wants a quick fix. The reality is this mission is difficult to execute alone and likely unsustainable over the medium to long term,” said Dana Stroul of The Washington Institute for Near East Policy and a former senior Pentagon official.

Risk of retaliation

The Pentagon has not provided operational details, including the number of ships involved, whether air support will be used, or whether regional allies will participate. Central Command declined to comment further.

Experts say a sufficiently large naval presence could deter commercial tankers from attempting to pass through with Iranian-linked oil. However, questions remain over whether U.S. forces would board, seize, or engage vessels that attempt to breach the blockade, particularly those carrying oil bound for major partners such as China, India, or South Korea.

Military officials and analysts also warn of possible Iranian retaliation. Retired Admiral Gary Roughead, former U.S. Chief of Naval Operations, said Iran could target ships or strike infrastructure in Gulf states hosting American forces.

“I honestly believe that if we begin to do it, Iran will have some kind of a reaction,” Roughead said.

Iranian threats against shipping have already contributed to a sharp rise in global oil prices, which have increased about 50% since the U.S. and Israel launched military action on February 28.

Trump acknowledged on Sunday that high oil and gasoline prices could persist in the United States through the November midterm elections, a factor that could influence political outcomes and public support.

Gas prices and escalation concerns

Frustrated by Tehran’s refusal to accept U.S. terms to end the conflict, Trump also raised the possibility of renewed strikes inside Iran, including against missile production facilities.

Senator Mark Warner, the top Democrat on the Senate Intelligence Committee, questioned the approach, warning that Iran could respond by mining the Strait of Hormuz or attacking commercial vessels.

“How is that going to ever bring down gas prices?” Warner said on CBS’ “Face the Nation.”

While U.S. military strikes have significantly weakened Iran’s conventional forces, analysts say Tehran retains asymmetric capabilities and has adapted its strategy, including maintaining stockpiles of highly enriched uranium.

Trump further escalated rhetoric on Sunday, warning that “any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!”

In response, Iran’s Islamic Revolutionary Guard Corps said any military movement toward the strait would be treated as a violation of the ceasefire and met with a “decisive” response, underscoring the risk of rapid escalation.

Dana Stroul said the crisis would ultimately require broader international engagement.

“Over the long run, this will need to be resolved through diplomacy and international political will,” she said. -Reporting by Phil Stewart; Editing by Sergio Non and Deepa Babington/Reuters